The field of wireless communications has many applications including, e.g., cordless telephones, paging, wireless local loops, personal digital assistants (PDAs), Internet telephony, and satellite communication systems. A particularly important application is cellular telephone systems for mobile subscribers. As used herein, the term “cellular” system encompasses both cellular and personal communications services (PCS) frequencies. Various over-the-air interfaces have been developed for such cellular telephone systems including, e.g., frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA). In connection therewith, various domestic and international standards have been established including, e.g., Advanced Mobile Phone Service (AMPS), Global System for Mobile (GSM), and Interim Standard 95 (IS-95). IS-95 and its derivatives, IS-95A, IS-95B, ANSI J-STD-008 (often referred to collectively herein as IS-95), and proposed high-data-rate systems are promulgated by the Telecommunication Industry Association (TIA) and other well known standards bodies.
Cellular telephone systems configured in accordance with the use of the IS-95 standard employ CDMA signal processing techniques to provide highly efficient and robust cellular telephone service. Exemplary cellular telephone systems configured substantially in accordance with the use of the IS-95 standard are described in U.S. Pat. Nos. 5,103,459 and 4,901,307, which are assigned to the assignee of the present invention and incorporated by reference herein. An exemplary system utilizing CDMA techniques is the cdma2000 ITU-R Radio Transmission Technology (RTT) Candidate Submission (referred to herein as cdma2000), issued by the TIA. The standard for cdma2000 is given in the draft versions of IS-2000 and has been approved by the TIA and 3GPP2. Another CDMA standard is the W-CDMA standard, as embodied in 3rd Generation Partnership Project “3GPP”, Document Nos. 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214.
Given the growing demand for wireless data applications, the need for very efficient wireless data communication systems has become increasingly significant. One such wireless data application is the transmission of data packets that originate or terminate at packet-switching networks. Various protocols exist for transmitting packetized traffic over packet-switching networks so that information arrives at its intended destination. One such protocol is “The Internet Protocol,”Request for Comments (RFC) 791 (September, 1981). The internet protocol (IP) breaks up messages into packets, routes the packets from a sender to a destination, and reassembles the packets into the original messages at the destination. The IP protocol requires that each data packet begins with an IP header containing source and destination address fields that uniquely identifies host and destination computers. The transmission control protocol (TCP), promulgated in RFC 793 (September, 1981), is responsible for the reliable, in-order delivery of data from one application to another. The User Datagram Protocol (UDP) is a simpler protocol that is useful when the reliability mechanisms of TCP are not necessary. For voice traffic services over IP, the reliability mechanisms of TCP are not necessary because retransmission of voice packets is ineffective due to delay constraints. Hence, UDP is usually used to transmit voice traffic.
The transmission of data packets from the IP network over a wireless communication network or from the wireless communication network over the IP network can be accomplished by adherence to a set of protocols, referred to as a protocol stack. Typically, a wireless communication device communicates with a base station(BS) and/or packet data serving node (PDSN) through an interface Um. A wireless communication device may be the origination or the destination of the IP packet, or alternatively, the wireless communication device may be a transparent link to an electronic device. In either case, payload information is broken into packets wherein header information is added to each packet. The IP header sits on top of the PPP layer, which sits on the RLP layer, which sits on top of the physical layer. The RLP layer is the Radio Link Protocol layer, which is responsible for retransmitting packets when a transmission error occurs. The packets are transported over the air to a BS/PDSN, whereupon the packet is subsequently sent over the IP network.
An issue that arises due to the nature of mobile communications is addressing. As stated above, the IP protocol requires that each data packet contains unique identifiers for the host and destination computers. Since a mobile communication device is capable of travelling from the range of one base station to another, a data packet addressed to the mobile communication device must be able to reach said device. Hence, some mechanism is needed to enable the continuity of data transfer when the mobile communication device is actually travelling. RFC 2002 (October 1996) proposes a solution to this problem. The protocol promulgated in this document enables a mobile communication device to change the point of attachment to the Internet without having to change the IP address of the device. Namely, RFC 2002 describes a registration scheme that informs a home agent of the location of a mobile communication device so that the home agent can route data packets through foreign agents.
However, the solution proposed by RFC 2002 is not optimal in that the registration procedure requires the usage of channel resources between the mobile communication device and network infrastructure elements. “Channel resources” is a term used generically to describe the transmission channel and the resources required to prepare a packet for transmission. In a CDMA system, such resources can encompass spreading codes, modulation symbols, and other processing elements. In particular, the registration and re-registration events consume valuable channel resources in order to maintain the point of attachment with the home agent. There is a present need to implement a registration and re-registration procedure that minimizes the consumption of channel resources.